250 PROCEEDINGS OF THE ACADEMY OF [April, 



Parapodia strictly uniramous, lateral, the first five or six more 

 ventral than the others. Neuropodium short, stout, bearing a fleshy 

 post-acicular lobe on anterior parapodia which disappears on middle 

 and posterior ones. Anterior to this is a row of conspicuous black 

 acicula and a rather complex group of seta?. Notocirrus of first 

 parapodium (III) rather stout, conical, tapering, simple, free from 

 but immediately above foot and about twice as long as the latter; 

 thence becoming gradually smaller caudad and in branchial region 

 reduced to a mere tubercle, but increasing in length again posteriorly. 

 Neurocirrus coalesced with base of neuropodium, consisting of a stout, 

 swollen cirrophore and a short, thick, cylinclroid, imperfectly differen- 

 tiated style; farther back the cirrophore merges more into the body 

 outline and the style becomes more slender but is otherwise unaltered. 



Gills simple, tapering filaments throughout. The first appears as a 

 minute papilla on the notocirrus of XVI to XX, but they are usually 

 not developed into efficient gills for several segments. At XXI or 

 XXII they are usually as long as the notocirrus; in the middle region 

 they reach the middle line and posteriorly gradually diminish in size 

 and finally disappear about twenty segments anterior to the pygidium. 



Acicula three to five anteriorly, simple, tapered, black, with pale 

 tips little or not at all exposed. They become gradually longer, 

 constantly three in number, conspicuous with prominently projecting 

 bluntly-pointed tips which are always pale with black cores. Some- 

 where between XX and XXX and on following segments an especially 

 large one diverges from the others and protrudes from the surface 

 between the neurocirrus and the compound setae. 



Setae all nearly or quite colorless, of three forms : two forms of simple 

 setae in supra-post-acicular fascicles and compound setae in sub-pre- 

 acicular fascicles. Compound setae (PI. VII, fig. 10) numerous, es- 

 pecially anteriorly where they occur in several rows anterior as well 

 as ventral to the acicula; farther back they become fewer and are 

 confined to the ventral group. The stems are gently curved and 

 very little thickened distally; the appendages very uniformly of a 

 length about four times the distal diameter of the stem with obscurely 

 hooked bidentate tips and a finely fringed border separating at the 

 tip into the usual guard. The fascicles of simple setae consist chiefly 

 of curved, capillary, slightly limbate or at least flattened setae (PI. 

 VII, fig. 8) considerably longer than the compound setae. Concealed 

 among the bases of the latter on the acicular side of the fascicle is a 

 group of very delicate gouge-shaped, pectinate setae (PL VII, fig. 9), 

 very few anterior^, more numerous farther back and apparently all 

 of one form. 



